Remove -webkit-*-before/after in:

chrome/browser/resources/chromeos/login/header_bar.css

Index: chrome/browser/resources/chromeos/login/header_bar.css
diff --git a/chrome/browser/resources/chromeos/login/header_bar.css b/chrome/browser/resources/chromeos/login/header_bar.css
index 0d435c64f0f18b31121253937f6b78e3675baa68..9d26fcb2d94cf98923ba2321c4951c1921cb423a 100644
--- a/chrome/browser/resources/chromeos/login/header_bar.css
+++ b/chrome/browser/resources/chromeos/login/header_bar.css
@@ -4,21 +4,21 @@
  */
 
 #login-header-bar {
-  -webkit-padding-after: 7px;
   border-bottom: 3px solid black;
   bottom: 0;
   left: 0;
+  padding-bottom: 7px;
   position: absolute;
   right: 0;
 }
 
 #login-header-bar {
-  -webkit-padding-before: 7px;
   /* Using copy of Ash launcher background with 0.8 opacity applied to it.
      Otherwise if opacity: 0.8 is set here it will affect button text as well.
      Have to position background differently so that opacity is not applied
      to child elements. */
   background-image: url('chrome://theme/IDR_LAUNCHER_BACKGROUND');
+  padding-top: 7px;
 }
 
 html[screen=lock] .login-header-bar-hidden,